Rhizobium strain, a banana (Musa spp.)-associated bacterium with a high potential as biofertilizer

ABSTRACT

A diazotrophic bacterial strain denominated 11B isolated from the rhizosphere of a banana plant (Musa spp.) was characterized morphologically, biochemically, and phylogenetically, whereas the symbiotic potential of the strain was assessed through tests of host range, interstrain nodulation competitiveness, and capacity to synthesize indole-3-acetic acid (IAA) and solubilize phosphate. Based on morphological and physiological–biochemical properties, as well as 16S ribosomal deoxyribonucleic acid (rDNA) sequence and phylogenetic analysis, the strain 11B belonged to the genus Rhizobium with 100.0% sequence similarity with Rhizobium tropici CAF440. The optimum growth temperature and pH for strain 11B are 28°C and 7.2, respectively. This strain was able to produce IAA, solubilize phosphate, and fix large amounts of nitrogen (N₂) and form effective nodules on the legumes Acaciella angustissima, Gliricidia sepium, Leucaena leucocephala, Lysiloma acapulcensis, and Phaseolus vulgaris. The rhizobial strain 11B was used successfully as a biofertilizer in agriculturally important legumes, forest trees, and agroindustrial plants.

KEYWORDS:

• Diazotrophic bacterial
• 16S rRNA gene
• symbiotic properties

Acknowledgments

We thank the Laboratory of Molecular Biology at the Instituto Tecnológico de Tuxtla Gutiérrez, Chiapas, Mexico, and the Laboratory of Ecology Genomics, Centro de Ciencias Genómicas (CCG) of the Universidad Nacional Autonoma de Mexico (UNAM) for technical assistance.

Funding

The project was funded by the Dirección General de Educación Superior Tecnológica (DGEST, Mexico).